In order to ensure product quality, it is necessary to detect an array substrate in a display panel during the production of the display panel. During the detection of the array substrate, it is mainly detected whether pixels in the array substrate are normal.
In the related art, the array substrate detection may be performed with a modulator including an internal electrode and a gold foil layer disposed opposite to each other, and a liquid crystal layer between the internal electrode and the gold foil layer. During the detection, the gold foil layer of the modulator gets close to the array substrate, a first voltage is applied to a pixel electrode of the array substrate, and a second voltage is applied to the internal electrode, such that an electric field is formed between the pixel electrode and the internal electrode. Incident light from one side of the array substrate exits from the other side of the array substrate, enters the liquid crystal layer in the modulator through the gold foil layer, and is reflected by the liquid crystal layer. Since normal pixels and defective pixels have different ability to maintain voltage, rotation capacities of the corresponding liquid crystal molecules will be different, and thus intensities of light reflected by the liquid crystal molecules will be different. Therefore, it is possible to determine whether a defect exists in the array substrate according to the intensity of the reflected light.
However, when a foreign matter such as glass debris or large particles exists on the array substrate, the foreign matter may damage the gold foil layer on the lower surface of the modulator, resulting in poor performance of the modulator. Then, the modulator has to be replaced to continue the detection. Therefore, the detection cost for the array substrate is high.